Comminuting mill



R. C. NEWHOUSE Aug. 12 1924.

COMMINU'IING MILL Filed March 15 1923 Patented Aug. 12, 1924.

UNITED STATES PATENT OFFICE.

RAY C. NEWHOUSE, OF WAUWA'I'OSA, WISCONSIN, ASSIGNOR TO ALLISCHALMERS MANUFACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF DELAWARE.

COMMINUTING MILL.

Application filed March 15, 1923.

To all whom it may concern:

Be. it known that RAY C. NnwHoUsE, a citizen of the United States, residing at Wauwatosa, in the county of Milwaukee and State of Wisconsin, has invented a certain new and useful Comminuting Mill, of which the following is a specification.

This invention relates in general to improvements in the construction and operation of comminuting apparatus and relates more specifically to an improved screening mechanism especially applicable to rotary cor'nminuting mills and the like.

An object of the invention is to provide simple means for enhancing the capacity and the efficiency of comminuting mills and of rotary screening devices therefor.

It has been found in the operation of com- Ininuting mills having annular rotary screens for grading the material delivered from the comminuting chambers, that unless some provision is made for automatically spreading and distributing the material delivered upon the screens, the screening surfaces become locally congested with material and wear out rapidly. This local congestion naturally reduces the screening and hence the discharge capacity of such mills. and the local wear necessitates frequent replacement of the screens. The present invention contemplates the provision of simple, efficient and automatically functioning means for distributing the material over the entire screening surface, thereby eliminating the objectionable congestion of material and local Wear on the screens.

Some of the novel features disclosed but not specifically claimed herein, form the subject of a copending application for Letters Patent, filed April 7, 1921 and bearing Serial No. 459,332. A clear conception of an embodiment of the invention and of the operation of devices constructed in accordance therewith, may be had by referring to the drawing ac-- companying and forming a part of this specification in which like reference characters designate the same or similar parts in the several views.

Figure 1 is a transverse vertical section through the division head of a combination comminuting mill provided with a screen for grading material delivered from the coarse grinding compartment of the mill.

Figure 2 is a fragmentary longitudinal Serial No. 625,222.

The rotary comminuting mill illustrated in Figs. 1 and 2 comprises generally a rotary shell orcylindrical drum 2 the interior of which is divided by means of a partition or division head 8, into successive comminuting chambers 3, 4 having freely tumbling comminuting bodies 5, 6 therein respectively. The division head 8 comprises an imperforate wall and a hold-backscreen 7 spaced laterally therefrom by means of radial ribs 19 which provide segregated discharge chambers 9 between the wall and hold-back screen. The hold-back screen 7 serves merely to prevent the coarse material and comminuting bodies 5 of the coarse grinding chamber 3, from entering the spaces 9, but does not prevent free passage of comminuted material from the chamber 3 to the spaces 9. The spaces 9 communicate through peripheral openings 18 with the screening chamber surrounding the drum 2 and located within the annular screen 12. In order to provide maximum and suflicient screening capacity, the screen 12 is laterally widened considerably beyond the side edges of the openings 18 leading from the chambers 9. For the purpose of preventing local delivery of material through these openings to the screen 12, each of the openings 18 leading from the chambers 9 is provided with a spreader 11 having a discharge directed oppositely of the direction of rotation of the mill. 'The spreaders 11 have outwardly and downwardly inclined guiding surfaces and also have laterally widened discharge edges 17 for effectively distributing the material over all portions of the laterally widened annular screen 12.

The relatively fine material passing through the screen 12 is delivered by gravity into a. receptacle 15 which may have liquid therein as indicated. The drum 2 adjacent to the division head and on the fine grinding side thereof, is provided with one or more peripheral scoops 16 adapted to remove material from the receptacle 15 and to discharge the material through members '20 into the fine grinding chamber 4 wherein are located the fine grinding or finishing comminuting body 6.

The oversize material which cannot pass through the screen 12 is automatically returned to the coarse grinding chamber 3 during the operation of the mill by means of return shoes 13 which during rotation of the mill deliver such oversize material through conduits 10 and return orifices 14 into a medial portion of the chamber 3.-

- widened discharge edges 17 of the spreaders 11 efi'ectively distribute the comminuted material over the entire surface of the annular screen 12. The particles of material which are suificiently fine'to pass through the perforations of the screen 12 are delivered by gravity into the receptacle 15. The larger particles which cannot pass through the perforations of the screen 12 roll along the inner surface thereof and are finally picked up by the shoes 13 and are delivered through the passages 10 and return openings 14 back into the coarse grinding chamber 3 for further reduction. The fine material deposited within the receptacle 15 is eventually removed and elevated by the scoops 16 which deliver the elevated material to the fine grinding chamber 4 of the mill through the injection nozzles 20. In the chamber 4 the fine material is further reduced by the tumbling comminuting bodies 6, the material being eventually discharged from the mill in a well known manner.

It will be obvious that the spreaders 11 efl'ectively distribute the material upon the annular screen 12 and prevent local congestion and consequent rapid wearing of the screen. By providing the spreaders 11 thescreen 12 may be laterally widened to permit free discharge of all material which has been sufliciently reduced, from the coarse grinding chamber 3, thereby permitting the comminuting bodies to act most efliciently upon the remaining particles.

It should be understood that itris not desired to limit'the invention to the exact details of construction hereinshown and described for obvious modifications may oc cur'to persons skilled in the art.

It is claimed and desired to secure by Letters Patent:

1. In combination, a rotary drum, an annular screen rotatable with said drum and having sidewalls, and a spreader located within said screen and between said walls, said spreader being formed to direct material delivered from said drum over all portions of said screen.

2. In combination, a rotary drum, an annular screen surroundin and rotatable with said drum, and a sprea er formed to direct material delivered from said drum over said screen in directions parallel to the axis of said drum.

3. In combination, a rotary drum having a peripheral discharge opening, a screen rotatable with said drum and having side walls, said screen and said walls extending axially of said drum beyond said opening, and a spreader located within said screen and between said walls, said spreader being formed to direct material delivered to said screen through said opening laterally over all portions of said screen.

4. In combination, a rotary drum form ing a comminuting chamber and having a peripheral discharge opening communicating with said chamber, a screen rotatable with said drum and extending transversely relative to the direction of movement of said drum beyond said opening, and a spreader for directing material from said opening laterally over said screen.

5. In combination, a rotary drum forming a comminuting chamber and having a peripheral discharge opening commimicating with said chamber, an annular screen surrounding and rotatable with said drum, said screen extending transversely relative to the direction of movement of said drum beyond said opening, and a spreader for directing material delivered from said opening laterally over said screen and in a direction opposite to the direction of rotation of said drum.

6. In combination, a rotary drum forming a comminuting chamber and having a series of peripheral discharge openings communicating with said chamber, an annular screen surrounding and rotatable with said drum. said screen extending longitudinally of said drum beyond said openings, and a spreader associated with each of said openings for directing material delivered through said openings over all portions of said screen and in a, direction opposite to the direction of rotation of said drum.

In testimony whereof, the signature of the inventor is ailixed hereto.

RAY C. NEWHOUSE. 

